Method for providing a cut around the anus of an animal, which is suspended from its back feet, to free the rectum from the carcass, and apparatus for performing said method

ABSTRACT

Method for providing a cut around the anus of an animal, preferably a hog, to free the rectum from the carcass, which is suspended at its back feet, according to which method a rotating, tubular knife is advanced towards the anus of the animal for making a cut around it in a predetermined depth. With the purpose of obtaining an automatized cutting process to free the rectum of animals, which may vary as to size and also be individually different, the method is characteristic in that the carcass is fixed with respect to a vertical plane through the axis of the knife, that the hind part of the carcass is fixed with respect to a vertical plane perpendicular to the first plane, that a linear sensor parallel with the second plane is moved downwards in a substantially vertical direction in such a distance from the second plane that it hits the root of the animals tail, and that the rotating knife is adjusted to a predetermined position with respect to the sensor, when it is hitting the root of the tail, after which the sensor is moved to an inactive position out of the way of the knife, whereafter the cut is made.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for providing a cut around theanus of an animal to free the rectum from a carcass suspended from bothits back feet. Furthermore, the invention relates to an apparatus forcarrying out said method.

On slaughter lines the carcasses of the animals are normally conveyedalong the line suspended from their back feet. Animal slaughter lineshave been established with many partially automatized functions. Afterscalding and removal of the outer layer of skin by means of hairshoving, black-singing and scraping, the animals are opened. One of thefirst stages of the opening is to free the rectum at the anus. Therectum is connected to the skin and should be cut free in such a waythat it is not damaged. For this purpose a cut is performed by means ofa knife around the rectum.

2. Description of the Related Art

On slaughter lines this cutting may take place manually, but as it is avery labor demanding operation, automatic devices for the operation havebeen proposed. A device of this kind is known from EP-A-258 939 andcomprises a positioning element to be inserted into the anus by amovement in the lengthwise direction of the positioning element. Thecutting operation is performed by a cutting element disposedconcentrically around the positioning element and displaceable in thedirection of its axis of rotation. In the known apparatus, the carcassis supported during the advancing of the positioning element by means ofa supporting bracket with a fork acting as a fixation for the carcassduring the cutting operation. The known device has no means foradjusting the position of the positioning element for adjust toindividual differences of the carcasses. This will exclude a totallyautomatic operation of the device.

SUMMARY OF THE INVENTION

The object of the invention is to provide a method, by means of whichcutting free of the rectum can be automated.

The invention is based on the observation that when carcasses aresuspended from both their back feet, the distance in vertical directionbetween the root of the animal's tail and the anus is subject to onlysmall variations. These variations are so small that the knife may beadjusted to its cutting position on the basis of measurement of theposition of the root of the tail. The carcass is then advanced axiallyon the condition that the animal before and after the measurement isfixed such that the root of the tail may be hit by a simple movement ofthe sensor. To meet this requirement, the animal is fixed by means of afixation means pressing against its back in the hind part of the animal.Preferably, the knife is provided with a gauge, which during the cuttingprocess is introduced into the anus. The guage prevents improperpositioning of a cut in an abnormally dimensioned animal. The gauge isalso used for activating the preparation for a new carcass, whereby theadjustment of the knife is changed slightly before the new operation isstarted. If the operation fails, an alarm to set off, and the operationmay then be carried out manually.

When the rectum has been cut free, the position of the animal and theopening made by the cutting may be used for the introduction of a knifewith a ball-point and for dividing the crutch of the animal. As aresult, more labor-consuming and awkward working process is avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to theaccompanying drawing, in which:

FIG. 1 shows a section through an embodiment of the apparatus accordingto the invention and through the conveying means on a slaughter line,and

FIG. 2 shows a section through the apparatus along the line II--IIaccording to FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The embodiment shown in the drawing of an apparatus for providing a cutaround the anus of a carcass for freeing the rectum comprises asupporting frame 1 connected with a support rail 2 for supportingcarcasses, which are suspended from their back feet by means of hooks 4arranged in pairs. The support rail 2 may run through the major part ofa slaughter line. The hooks 4 are mounted a predetermined distance fromone another by a fixation means in each pair of hooks. Advancing means 5are adapted to advance the carcasses along the support rail 2 and forfixing the animals for as long as required at each working station.

The main support frame 1 comprises a pair of vertical positioningcolumns 6, along which a second frame 7 is displaceable in a verticaldirection. The second frame 7 is displaced by means of a hydrauliccylinder 8 or corresponding driving means connected to the upper part ofthe main support frame. A positioning means 9 for a rotating knife 10provided with a driving means is pivotally mounted on the second frame7. The positioning means is pivotal in a vertical direction around aswinging shaft 11 by means of a hydraulic cylinder 12. The piston 13 ofthe hydraulic cylinder 12 is connected to a console 14 on thepositioning means 9. By means of the hydraulic cylinder it is possibleto change the angle of the longitudinal axis of the rotating knife fromapprox. 45° as shown in the drawing to approx. 60° with the horizontalplane. The rotating knife 10 comprises a centrally placed gauge 15protruding somewhat in relation to the edge of the knife. An advancingmeans 16 for a knife 17 with a ball-shaped point is pivotally connectedto the second frame 7. The angle of the advancing means 16 is adjustableby means of a hydraulic cylinder, which is not visible in FIG. 1 onaccount of the cylinder 12, and the piston of which is in gear with aconsole 19 placed on the advancing means 16. From FIG. 2 it can be seenhow the two advancing means are mounted side by side on the second frame7.

A sensor arm 20, mounted on the second frame, is arranged for adjustingthe height of the second frame. The sensor arm is pivotal around ahorizontal axis by means of a driving means 21, enabling an activehorizontal position shown in the drawing and an inactive, verticalposition. The sensor arm is provided with a contact sensor, emitting asignal for the activation of the cutting operation.

In the lower part of the animal's body, fixation means 22 pressesagainst the back of the carcass.

An automatic free-cutting of the rectum of the carcass can be carriedout while using the method according to the invention. At the end of aworking operation the apparatus is positioned in its uppermost position,in which the piston of the cylinder 8 is withdrawn into the cylinder. Bymeans of the advancing means 5, a carcass 3 is placed and fixed in frontof the apparatus. During the fixation, depending on the size and shapeof the animal the carcass is pushed slightly away from the apparatus bymeans of the fixation means 22 so that the carcass rests against thefixation means. On account of this, the hind of the carcass will befixed in such a way that the tail of the carcass will be positioned in acertain vertical plane in front of the apparatus. This occurs withnarrow limits, irregardless of the size of the animal. Then the secondframe 7 is lowered until the sensor arm 20, which has taken up ahorizontal position, contacts the root of the animal's tail. The contactactivates the contact sensor, which starts the cutting operation. Atfirst the sensor arm is pivoted into a vertical position, then therotating knife is advanced towards the animal until the gauge 15penetrates about 20 mm into the anus of the animal. The hollow space inthe inside of the knife is then connected to a vacuum source in order tosuck up any content from the rectum, which may get out during thesubsequent cutting. The knife is tilted to a position, in which it is atan angle of 60° to relative to the horizontal plane during the furtheradvancing of the knife 10. When a predetermined cutting depth has beenreached, the rectum is cut free and the rotating knife can be withdrawn.The rotating knife comprises disinfecting means, which are activatedafter each cutting operation, preferably when no carcass is present infront of the apparatus. After the cutting operation, the rotating knifeis brought back into the position in which it forms an angle of 45°relative to the horizontal plane.

The apparatus of the preferred embodiment is provided with a cuttingdevice which divides the animal through the crutch. The cutting devicecomprises the advancing means 16 and is tilted into a position in whichit forms an angle of approx. 45° relative to the horizontal plane. Theknife 17 is brought forward into the cut in the animal. When theadvancing means has returned to the position shown in the drawing, theknife 17 will divide the carcass through the crutch, after which theknife returns to its starting position. Finally, the support framereturns to its starting position, in which the sensor arm is lifted fromthe carcass, and the carcass is then conveyed further down the line bymeans of advancing means 5. A new operation is then initiated when a newcarcass is brought into position in front of the apparatus.

I claim:
 1. A method of automatically positioning and cutting an animalcarcass for removal of its rectum, comprising the steps of:supportingthe carcass; positioning the carcass such that its hind is fixed in apredetermined position; sensing the location of the root of the animalcarcass tail; positioning a rotating cylindrical knife relative to thelocation of the root of the carcass tail; inserting a gauge into theanimal carcass anus to a predetermined depth; advancing the knife to acutting position; and cutting around the anus with the knife to thepredetermined depth.
 2. A method as recited in claim 1, wherein saidsensing step comprises:moving a sensor arm to a sensing position;lowering the sensor arm until it contacts the root of the animal carcasstail; and retracting the sensor arm from the sensing position after saidpositioning of the rotating cylindrical knife.
 3. A method as recited inclaim 2, wherein said moving and retracting of said sensor arm into andout of said sensing position is performed by a pivoting motion.
 4. Amethod as recited in claim 1, wherein said carcass is supported in avertical plane.
 5. A method as recited in claim 4, wherein the knife isadvanced at an angle of 45° relative to the vertical plane.
 6. A methodas recited in claim 1, wherein said predetermined depth is about 20 mm.7. A method as recited in claim 1, further comprising the step ofconnecting the knife to a vacuum source during cutting.
 8. A method asrecited in claim 4, wherein, during cutting, the knife is disposed at anangle of 60° relative to a horizontal plane perpendicular to thevertical plane.
 9. A method as recited in claim 1, further comprisingthe steps of:moving a second knife into a hole resulting from thecutting step; and pivoting the second knife such that the carcass issplit at its crutch.
 10. An apparatus for automatically positioning andcutting an animal carcass for removal of its rectum, said apparatuscomprising:means for supporting the carcass; means for positioning thecarcass such that its hind is in a predetermined position; means forsensing the location of the root of the carcass tail; means forpositioning a rotating cylindrical knife relative to the location of theroot of the carcass tail; a gauge attached to said knife, said gaugebeing inserted into the carcass anus to a predetermined depth; and meansfor advancing said knife to said predetermined depth.
 11. An apparatusaccording to claim 10, wherein said supporting means comprises:a frameadapted to support the carcass; and a suspension hook attached to saidframe, said suspension hook suspending the carcass from its back feet.12. An apparatus according to claim 10, further comprising:a first framefor supporting the carcass; and a second frame attached to said firstframe, said second frame adapted for vertical displacement within saidfirst frame relative to said carcass, wherein said second frame supportssaid sensing means, said cutting means, and said advancing means.
 13. Anapparatus according to claim 12, wherein said sensing means comprises asensor arm pivotally attached to said second frame, said sensor armbeing pivotal into and out of a sensing position.
 14. An apparatusaccording to claim 10, wherein said gauge is arranged coaxially withinsaid rotating cylindrical knife.
 15. An apparatus according to claim 10,wherein said supporting means supports said carcass in a vertical plane.16. An apparatus according to claim 15, wherein said advancing means ispivotally attached to said second frame, enabling said knife to beadvanced at an angle between 45° and 60° with respect to a horizontalplane perpendicular to said vertical plane.
 17. An apparatus accordingto claim 13, wherein said sensing arm comprises a rod having a contactsensor sensing contact with the root of the carcass tail, said contactsensor activating cutting of the carcass.
 18. An apparatus according toclaim 12, further comprising a second knife pivotally attached to saidsecond frame for splitting the carcass at the crutch.